二氧化钛纳米管阵列制备和光催化降解甲基橙

采用电化学阳极氧化的方法,以氟化铵水溶液为电解液,在纯钛表面制备了TiO2纳米管阵列。以甲基橙为模拟污染物,考察了TiO2纳米管阵列光催化降解效果。结果表明,TiO2纳米管阵列催化降解效果要好于TiO2薄膜电极,60、120和180 min时,降解率分别为56%、88%和100%;而TiO2薄膜电极的降解率分别为43%、76%和91%。在此基础上,考察了阳极氧化电压、氧化时间和焙烧温度对阳极氧化过程的影响规律。结果表明,阳极氧化电压在10～25 V,氧化时间在1～2 h,焙烧温度在500℃时所制备的TiO2纳米管阵列光催化降解性能最好。     

纳米TiO2/Ti管阵列薄膜催化剂的制备和性能

采用阳极氧化法制备纳米TiO2/Ti管阵列薄膜催化剂,考察了外加电压、反应时间和电解液pH值对催化剂形貌的影响.结果表明,在外加电压20 V,pH值为4.5～5.0,反应6 h的条件下,制得的TiO2管阵列薄膜催化剂管孔形貌清晰、整体分布均匀,管长约为1.8,um,管径约为90 nm.在400℃煅烧2 h后,由无定型转化为单一的锐钛矿型,阵列结构没有崩塌和损毁.在400℃煅烧后的纳米TiO2/Ti管阵列薄膜催化剂具有良好的光催化活性,可与光电协同催化用于降解亚甲基蓝,光催化和光电协同催化降解的降解率分别为21.30%和77.96%.     

钆掺杂二氧化钛纳米管光催化降解制药废水

采用阳极氧化法制备TiO2纳米管阵列,并在制备TiO2纳米管阵列的同时掺杂钆元素,形成钆掺杂TiO2纳米管阵列,研究其光催化降解制药废水的性能。结果表明,经过450℃煅烧的催化剂,在碱性条件下,钆掺杂浓度为0.007 5 mol/L时,催化效果最好,光催化5 h后,制药废水降解率达到97.41%,且该催化剂稳定性好,可重复使用。     

TiO2纳米管阵列电催化降解甲基橙

采用阳极氧化法制备了TiO2纳米管阵列电极,通过考察其对模拟染料废水甲基橙(MO)的光催化降解效率来优化制备条件。研究了TiO2纳米管阵列电极电催化降解MO的活性及其影响因素,并考察了MO降解反应动力学。结果表明,MO溶液pH、电解槽压、支持电解质浓度等是TiO2纳米管阵列电极催化效率的重要影响因素。TiO2纳米管阵列电催化降解MO的反应遵守一级反应动力学规律,与TiO2纳米管阵列光催化降解MO的行为一致,且表观反应速率常数不随MO溶液浓度不同而发生改变。     

TiO_2电极制备、表征及光电催化研究

文章采用阳极氧化法制备了TiO2纳米管电极、TiO2膜电极,对其进行了SEM、XRD表征的比较。研究了电化学过程、光解、TiO2纳米管的光催化、TiO2纳米管电极的光电催化对五氯苯酚的降解,研究表明光电催化降解速度最快。此外,TiO2纳米管电极和TiO2膜电极对五氯苯酚的光电催化降解也进行了研究。结果表明,TiO2纳米管电极对五氯苯酚光电催化效果明显好于TiO2膜电极,2h二者的降解率分别为81.5%,69%。     

TiO2纳米管阵列膜光催化降解苯胺

利用TiO2纳米管阵列光催化降解含苯胺水样,考察了影响苯胺降解率的各种因素。结果表明,在照射光源波长254 nm,反应时间120 min和苯胺水溶液pH=9时,TiO2纳米管阵列光催化氧化苯胺的效果最好,苯胺降解率达到87%;另外在苯胺水样中加入含Fe3+、Cu2+的金属盐和少量的H2O2氧化剂后,对TiO2纳米管阵列的催化活性具有促进作用,其苯胺降解率分别提高了42%、31%和19%。探讨了TiO2纳米管阵列光催化降解苯胺的反应机理。     

纳米二氧化钛管阵列的制备及其光催化氧化降解甲基橙性能的研究

本文采用电化学阳极氧化法制备了管径为90—150nm的纳米管阵列。采用SEM和XRD对制备的二氧化钛纳米管阵列进行了表征。考察了焙烧温度对阳极氧化法制备纳米二氧化钛管阵列晶形结构的影响。将所制备的纳米管用于光催化降解甲基橙反应,考察了其在通气和不通气条件下光催化降解甲基橙的性能。结果显示：在550℃下焙烧的纳米管阵列具有良好的催化活性;反应器中通氧气可以提高纳米二氧化钛对甲基橙的光催化活性。     

二次阳极氧化制备TiO_2纳米管阵列及光催化性能研究

采用二次阳极氧化法制得高度有序的TiO2纳米管阵列,并与一次阳极氧化法制备TiO2纳米管的形貌和光催化活性进行了比较。利用FESEM和XRD表征分析纳米管阵列的形貌和结构。研究结果表明:二次阳极氧化法制备的TiO2纳米管阵列克服了一次阳极氧化法制备的TiO2纳米管的表面粗糙有絮状物、管长不均等缺陷,制备出表面平滑,长度均匀的TiO2纳米管阵列,相同条件下与一次阳极氧化制得的TiO2纳米管的光催化降解速率进行对比,前者比后者提高了近一倍。     

电解液对TiO2纳米管阵列薄膜光电催化性能的影响

采用电化学阳极氧化法,在HF—H2O,NH4F—H2O,NH4F—H2O-乙二醇三种不同的电解液体系中,于Ti基底上制备了TiO2纳米管阵列薄膜,并在空气气氛中于500℃进行结晶热处理。以亚甲基蓝为模拟污染物,考察了TiO2纳米管阵列薄膜的光电催化降解效果,并比较了电解催化、光催化和光电催化对亚甲基蓝溶液降解效率的差异。结果表明在NH4F—H2O-乙二醇电解液体系中制备的TiO2纳米管阵列光电催化性能最好。经过340min后,催化效率达到了94．23％。     

TiO2纳米管阵列电极电催化降解甲基橙的研究

采用阳极氧化法制备了TiO2纳米管阵列电极。采用场发射扫描电子显微镜(FESEM)和X-射线衍射仪(XRD)表征了电极的表面形貌和晶体结构,应用电化学阻抗谱(EIS)技术研究了不同阳极极化电位下电极的导电性能,应用荧光光谱法研究了电极产生羟基自由基(·OH)的活性,考察了3种支持电解质(Na2SO4、NaNO3和NaCl)对甲基橙(MO)电催化降解效率的影响,通过加入捕获剂探讨了MO分子的降解机理。结果表明,TiO2纳米管阵列电极电极的导电性随阳极极化电位的升高而增强;在电场作用下,TiO2纳米管阵列电极表面生成大量·OH;Na2SO4和NaNO3不参与MO分子的氧化反应,MO的降解符合一级反应动力学模型,而NaCl参与了TiO2纳米管阵列电极电催化降解MO的过程,呈现出复杂的动力学行为;在捕获剂存在的情况下,MO分子仍能发生降解,显示MO分子可在TiO2纳米管阵列电极表面直接氧化。     

Synthesis and growth mechanism of multilayer TiO2 nanotube arrays

High-aspect-ratio TiO(2) nanotube arrays formed by anodic oxidation have drawn extensive attention due to their easy fabrication and various excellent optical, electrical and biomedical properties. In contrast to conventional single-layer TiO(2) nanotubes prepared via constant-voltage anodization, we synthesize multilayer TiO(2) nanotube arrays with high surface area by using alternating-voltage anodization steps. This work presents synthesis and growth mechanisms of single-layer smooth TiO(2) nanotubes, bamboo-type nanotubes and double-layer nanotubes, by tuning various parameters such as voltage, time, and water content in the electrolyte. It is found that ion diffusion inside the nanotubes dominates growth of these three structures. A stable pH and ion-diffusion profile allows the steady growth of smooth TiO(2) tubes in NH(4)F-containing ethylene glycol (EG). The addition of a low-voltage anodization step reduces the pH and ion-diffusion gradient in the nanotubes and induces formation of bamboo-type nanotubes and double-layer nanotubes when a second high-voltage anodization is conducted. Ion diffusion through a nanotube takes time; thus formation of lower-layer TO(2) nanotubes costs more time if longer nanotubes are grown in the upper layer, since ions diffuse through these longer nanotubes. This ion-diffusion controlled growth mechanism is further confirmed by tailoring the water content (0-20 vol%) in the electrolyte and the voltage gaps to control the time needed for initiation of lower-layer TiO(2) nanotube arrays. The fundamental understanding of the growth characteristics of double-layer TiO(2) nanotubes presented in this paper offers us more flexibility in engineering morphology, tuning dimensions and phase compositions of multilayer TiO(2) nanotubes. In addition, we synthesize double-layer TiO(2) nanotube arrays composed of one layer of anatase phase and another layer of amorphous phase.     

TiO2纳米管电极光电催化氧化工艺对罗丹明B的脱色

在平面转盘光电液膜反应器的基础上,以纳米管TiO2代替溶胶凝胶法制备的TiO2纳米颗粒结构,以提高对染料废水的脱色效果。在0.5%HF体系和20 V电压下,采用阳极氧化法制得纳米管TiO2膜电极,根据光电响应试验的结果,选取120 min作为氧化时间。以RhB为目标污染物,应用转盘光电液膜反应器,在UV照射下进行脱色研究。结果表明在光催化和光电催化过程中,纳米管TiO2膜电极对RhB的脱色率分别达89%和94%,比溶胶凝胶电极分别提高了66%和10%。最佳脱色条件:转速为80 r/min,偏压为0.8 V。且在处理高浓度的RhB溶液时,纳米管电极的优势更加明显。     

Fabrication of high aspect ratio and open‐ended TiO2 nanotube photocatalytic arrays through electrochemical anodization

Well‐aligned, high aspect‐ratio and open‐ended TiO₂ nanotube arrays secured within a Ti foil (TiO₂ nanotubes cartridge) were successfully prepared through the double‐sided anodization method. With ～210 µm of nanotube length, the anodic growth of TiO₂ was accelerated and stabilized by the lactic acid‐containing ethylene glycol electrolyte. In the absence of lactic acid, the anodization led to detachment of nanotubes from the Ti foil after 5–6 h of high voltage (80 V) anodization. Transmission electron microscope image and Raman spectrum revealed that the as‐anodized TiO₂ nanotube arrays without annealing treatment were partially crystalline anatase and demonstrated photocatalytic activity in the mineralization of formic acid. © 2015 American Institute of Chemical Engineers AIChE J, 62: 415–420, 2016     

电压施加方式在阳极氧化钛薄膜形成过程中的作用

采用阳极氧化的方法,通过改变电压的施加方式制备了具有不同形貌的氧化钛薄膜。使用扫描电子显微镜考察了氧化钛薄膜的形貌,结合实验现象探讨了阳极氧化钛薄膜纳米孔的形成机制。研究结果表明,采用一步施加电压和连续施加电压的方法,氧化钛薄膜纳米孔的形成过程由电压、阻挡层的厚度决定;采用两步施加电压的方法,氧化钛薄膜纳米孔的形成过程由放电电压、阻挡层的厚度和阻挡层/电解液的边界条件协同控制。在相同工艺条件下,采用两步施加电压法能够扩展阳极氧化钛薄膜纳米孔孔径和孔密度的范围。     

聚硅硫酸钛制备复合光催化剂及降解甲基橙的研究

以无机钛盐、硅酸盐为原料,制备了聚硅硫酸钛絮凝剂,然后利用其水溶液水解产物制备复合光催化剂,考察了钛与硅摩尔比、水解pH值、调节pH值所用碱的种类、煅烧温度和煅烧时间对该复合光催化剂降解甲基橙时活性的影响,并利用扫描电镜（SEM）和X射线衍射（XRD）对其进行了物性测试分析。结果表明：n（Ti）：n（Si）=12：1的聚硅酸硫酸钛,以NH3.H2O调节pH值,在pH值为6时水解,产物在650℃煅烧1.5h后制得的复合光催化剂活性最高,当其投加量为0.5g.L-1时,光催化反应30min后,甲基橙的脱色率可达100%。物性分析表明,聚硅钛制备的复合光催化剂是一种以锐钛矿为主、分散均匀的纳米级球形颗粒。     

敏化对微弧氧化TiO2膜光催化性能的影响

采用微弧氧化法以磷酸钠为电解液在钛片上制备TiO2膜,通过对苯胺废水的光催化降解率来表征TiO2膜的光催化性能,采用溶胶-凝胶和敏化处理对TiO2膜进行改性。实验结果表明:用溴甲酚绿敏化溶胶-凝胶法负载两次的TiO2膜,当溴甲酚绿敏化剂的质量浓度为20 mg/L,pH为5,敏化时间为16 h,TiO2膜的光催化效率达到40.6%。     

Effect of synthesis highly ordered TiO<Subscript>2</Subscript> nanotube arrays with enhanced photocatalytic properties by time,electrolytic voltage,heating temperature and Polyvinyl pyrrolidone

Highly ordered TiO₂ nanotube arrays were prepared by anodization method with doped Polyvinyl pyrrolidone (PVP) addition. The as-prepared samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscopy. The results suggested that TiO₂ nanotubes arrays modified by 0.10 wt% PVP were better uniform and more highly ordered than that of pure TiO₂. The average inner diameter and the tube length of TiO₂ nanotubes were extended approximately 77 nm and 5.21 μm, respectively. Meanwhile, the optimum synthesis conditions (40 V, 4 h and 450 °C) were determined by SEM and XRD. In addition, the photocatalytic activity of the as-prepared samples was investigated for the degradation of RhB under UV-lamp irradiation. The results showed that almost 100 % of RhB was degradation within 80 min by the as-prepared nanotubes in the optimum synthesis conditions. It was indicated that the photocatalytic activity of the as-prepared nanotubes was improved greatly due to their well morphology, enhanced UV-light absorption property and electron transmission ability. In general, this study could provide a principle method to synthesize TiO₂ nanotube arrays with enhanced photocatalytic activity and improved microstructure by anodization process with PVP addition.     

高活性易分离TiO_2光催化剂的制备

用四氯化钛为原料,经氨水沉淀、水洗、无水乙醇洗涤得到Ti(OH)4醇凝胶,对Ti(OH)4醇凝胶进行乙醇热处理、干燥、焙烧制得了TiO2粉体。以光催化降解活性艳红X-3B作为模型反应,考察了所制得的TiO2粉体的光催化性能。发现140℃乙醇热处理10 h制得的TiO2经800℃高温焙烧后仍具有与Degussa P25 TiO2相当的光催化降解X-3B活性。而且沉降性好,易分离。     

TiO2-硅藻土复合光催化剂降解二甲基甲酰胺研究

以硅藻土为固体活性添加物,采用溶胶-凝胶法水解钛酸四丁酯制备硅藻土负载TiO2复合光催化剂。以二甲基甲酰胺(DMF)溶液的光催化降解为模型反应,研究制备条件中煅烧温度、溶胶pH值、H2O与Ti(OR)4的量比、涂覆次数等条件对光催化活性的影响。结果表明,合成复合催化剂的最佳煅烧温度为500℃、溶胶pH值为1.3、H2O与Ti(OR)4的量比为15.75、涂覆次数为3次;在300W紫外光照射、反应2h、催化剂投量为1g/L、DMF的质量浓度为200mg/L时,最大降解率为84.27%,表现出较强的光降解性。